//省略号
@mixin omit{
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
//清除浮动
@mixin clearfix{
  zoom: 1;
  &:after {
    content: ".";
    display: block;
    height: 0;
    clear: both;
    visibility: hidden
  }
}
